Mineral diesel is the main source of energy used worldwide and the most explored as a transportation fuel, however, it possess several disadvantages like; the sources of crude petroleum are limited and burning of diesel in engines causes the environmental hazardous problems. Moreover, diesel is a non-renewable source of energy. Additionally, availability of crude petroleum is confined to some areas of the world. Consequently, oil dependency of any nation on other nation poses a great threat for the security of oil deficient nations. Therefore, in order to circumvent these problems and to reduce the dependence on the fossil fuel, scientists have been prompted to look into alternate synthetic diesel fuel.
Last ten years have been focused on the benefits of producing cleaner, cost effective fuels process based on Fischer Tropsch technology that utilizes clean natural gas. Synthetic diesel finds applications in many diverse segments. The use of synthetic diesel in diesel engines results in substantial reduction of un-burnt hydrocarbons, carbon monoxide and particulate matters and is considered as a ‘clean fuel’.
Unlike conventional diesel fuel which is produced as fractional distillate from petroleum, synthetic diesel is produced by Fischer-Tropsch process, wherein biomass, natural gas or coal is gasified to synthetic gas and subsequently liquified to produce synthetic diesel. Such processes are called Biomass-To-Liquids (BTL), Gas-to-Liquid (GTL) and Coal-to-Liquid (CTL) respectively. Such synthetic diesels are sometimes called FTD (Fischer-Tropsch diesel).
Synthetic diesel fuels are attractive because they are designed to provide both good engine performance and emission reductions. Use of synthetic diesel results in significant reductions in emissions, including NOx and particulate matter. Synthetic diesel fuels are characterized by excellent properties, such as very high cetane number and nil sulfur content. They can be used in existing diesel engines without modifications or mixed with petro-diesel. Synthetic diesels are even potentially suitable for aviation fuels with higher flashpoints.